Thank God for Liam Neeson, or possibly Herman Staats. On the morning of July 11 2000 Staats was driving his truck along a back road in upstate New York when he came across a dead deer, a ruined Harley Davidson, and a Hollywood star in an advanced state of disrepair. "I can remember every nanosecond of that crash," says Neeson, who possesses a soft Antrim brogue and the delivery of a born raconteur. "It was like something out a David Lynch movie. That deer coming out of nowhere and just climbing over the front of my motorbike. At one point she had her forelegs over the handlebar and her face was right here." He indicates a space in front of his nose, then pauses for effect. "I remember feeling her breath and knowing that she could feel mine, and just locking eyes with this other live creature. For that moment we were very much in sync."

Staats, the local Samaritan, discovered him on the hard shoulder. "He had managed to crawl his way back up the road," the trucker told reporters. "He wanted me to drive him back to his house, but I could tell his hips were bothering him." In fact the actor's pelvis had been shattered in the crash. The press suggested he might never walk again.

So for a man who might be dead or permanently disabled, Liam Neeson is doing rather nicely for himself. Fresh off his crutches, he hobbled through a role as the martyred patriarch in Gangs of New York and twinkled gamely through Love Actually. "But I didn't get back on the bike," he admits. "That finished me with bikes. The thing was in bits anyway."

His latest film, Kinsey, may well be his finest work to date. Alfred Kinsey's pioneering sex research scandalised 1940s America, and Neeson plays him as a fascinating cocktail of repression and candour - the mid-western puritan in the guise of a roué. Or is it the other way around? With Kinsey it's sometimes hard to tell.

The moral majority have their own line on Kinsey, of course, and have gone out of their way to protest about Bill Condon's biopic. According to organisations such as Morality in Media or Concerned Women For America, the sexologist was a dirty old man who sent America to hell in a handcart, a pervert whose legacy is "Aids, abortion and pornography". Neeson scoffs at such notions, but admits there were different facets to the man. "He was most certainly a gifted and objective scientist, but behind it all there was a social reformer there too. And, like any man or woman of achievement, he became obsessed with his subject matter."

Is this something he can relate to in his own work? "No, I don't get obsessed with acting," says Neeson. "Because in the past when I have got obsessed about it, it really got in the way of the creative process. I've learned to hang the character on the coat-peg at the end of the day, and when I leave in the morning I pick it up again. And I had to work at that because the other way lies a strange sort of madness."

When I mention that his wife - the actor Natasha Richardson - has described him as "a laid-back guy" he blinks in surprise. "Laid-back? My wife said that? Well, I guess I am. It takes a lot to get me riled."

Even so, you wouldn't want to risk it. There is an old prejudice about Hollywood stars that they play tough on screen and play golf off it; that they are spoilt, shy, and invariably much smaller in the flesh than they seem in the movies. But Neeson, who looms 6ft 4in, hardly fits with the stereotype. Before treading the boards at Belfast's Lyric theatre he was an amateur boxer by night and a fork-lift truck driver by day. He claims to still keep himself in pretty good shape and says that's what helped him survive the crash.

Why does he think that most big actors are quite small people? "Small? Are they? Like who?" Well, Tom Cruise, for instance. Or Al Pacino. Dustin Hoffman. "Well, I don't know," says Neeson, nonplussed, "I never really thought about it. I mean, I saw Clint Eastwood out in LA last week, and he's definitely 6ft 3in. And Pacino's small, but he's huge on screen. I have met Tom, and I guess he is small, but I never looked at him and thought, 'Gosh, you're small'." He pauses. "Colin Farrell is quite a tall man. Brad Pitt's quite tall. I'll tell you who is small ... No, I'm not going to say that." Oh go on, spill the beans. "No," he says. "It was just a daft thought, I was thinking aloud. I better not say."

Experience has taught him to be cautious. A couple of years back a US magazine ran an interview in which he recalled his upbringing in Ballymena, Co Antrim. Growing up Catholic in a predominantly Protestant town, he said, made him feel like a "second-class citizen". Moreover, he remembered having to stay indoors during the annual Orange walk commemorating "some bloody obscure war where some bloody Catholic king was defeated by some bloody Dutch king who was Protestant".

When Ballymena offered him the freedom of the town these comments were duly dredged up and held against him. In the end the row grew so heated that he decided to reject the honour. "But of course then that becomes the story," he sighs. "You very graciously decline and that becomes the thing people fix upon. So you're cursed if you do and you're cursed if you don't. Either way you end up splashed across the front of the Belfast Telegraph. I hate all that controversy, absolutely hate it."

For the record, Neeson insists that he is very proud of Ballymena. He still has family there, still regards it as his hometown. Furthermore, he points out that he was head boy at a Catholic school, so things can't have been as bad as all that. Of course, there were downsides. Antrim in the 1960s was a fairly strait-laced - if not actively repressed - environment, rather like America before Kinsey shone his light on it. "Certainly sex was not top of the agenda," he admits. "It was a healthy upbringing, particularly bearing in mind all that was happening in Northern Ireland at the time. But sex wasn't up for discussion, not even at school. It was just never talked about. And I guess that what you don't have, you don't miss."

So he wasn't a secret bedroom masturbator? "Er," says Neeson. "Well yes, of course. But that's all part of the fun. What was it that Billy Connolly said? I remember him asking me: 'Did you ever do the dead man's shuffle?' And apparently that's where you lie on one arm until it goes dead and then when you masturbate it feels like someone else is doing it to you." He shakes his head in wonder. "The dead man's shuffle. That's one I never tried."

Neeson recently completed a role in Ridley Scott's Kingdom of Heaven, battling the Moors in the deserts of Morocco. Further afield, there is a mooted role as Abraham Lincoln, the founder of the Republican party back when it was on the more liberal, progressive wing of American politics. Inevitably, the film - which would reunite the actor with his Schindler's List collaborator - should generate still more controversy. "Well, I have been approached by Steven Spielberg to play him," Neeson explains. "But Steven has a big backlog of films and it's still very early stages. So maybe next year sometime. But Jesus, would I be honoured to play Abe Lincoln."

Spielberg's picture will be based on a biography by Doris Kearns Goodwin. However, Neeson stresses that he will be reading as widely as he can, immersing himself in everything to do with the Republican party icon. One recent work that he might care to investigate is titled The Intimate World of Abraham Lincoln. Its big revelation is that the president was actually homosexual - that he shared a bed with his bodyguard and enjoyed a long-standing affair with a "youthful friend".

Best of all, its author once worked as a researcher for Alfred Kinsey. "Yes, that's right," says Neeson, "Clarence Tripp, who spent 20 years studying the writings of Lincoln and came up with these conclusions. He's passed away now, Clarence Tripp, and the book was published posthumously. I've seen a review of it and it will be interesting to read, certainly. I've got to get my hands on as much information as I can."

Play Lincoln as gay, I tell him. Just for the fun of it. "Oh yes," says Neeson. "I can just imagine what the moral majority would make of that."